Scrub brush



FIG. 1 is a front perspective view of the scrub brush, showing my new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a rear perspective view thereof;

FIG. 4 is a bottom plan view thereof.

The brush is substantially symmetrical about its longitudinal axis. 

The ornamental design for a scrub brush, as shown and described. 